In many applications, access is required to centrally stored information by computing devices at remote sites. In one example, there is a need to retrieve the most current information from a central database for presentation at a remote site. Communications between the central database and the remote site can be quite complicated if there are many remote sites attempting to access the central database concurrently. One popular approach for managing these communications is the use of a client/server model for data distribution. The data server interfaces with the central database to provide orderly access to the data by data clients at the remote sites. Thus, a client needing information from the central database makes a request to the database server, and the database server responds to the client with the information sought.
There are some problems which arise in the server/client model, which are particularly acute when the remote sites are connected through a wireless communication link. One such problem is the general limited transmission capacity for communications between the server and the client. This problem is magnified when the amount of data transferred is relatively large, and data requests are frequent in order to keep information current at the remote site for a critical application. For example, consider a remote client in the form of a wireless computing device which maintains and presents graphical images to an operator. The presentation of images typically requires large quantities of data. If the image data must always be kept fairly current, information must be transferred from the central database to the computing device. However, the data transmission capacity of the communication link between the client and the server places an upper limit on the quantity of data which may be transferred within a specific time period. Thus, there is a need to minimize the amount of data transmitted.
Many prior art solutions focus on the efficient and timely transfer of information between a centrally located data server and a remote client. Some prior art solutions focus on data compression. Data compression seeks to condense information, usually by removing useless repetition of data, such that the total amount of information transferred is reduced. Another focus is on the provision of more high speed transmission capacity. By increasing the data transmission rate, the total time required to transfer information from the server to the client is reduced.
There has been an increase in the use of wireless communication devices, for the presentation of images, or other types of documents to an operator. Many applications require the transfer of large quantities of data. Computation and/or storage capabilities may differ depending on the type of device available to the operator. For example, in one case, the operator may be interfacing directly to a powerful work station. In another case, the operator may be using a less powerful hand-held computing device. Differences also exist for the data transmission links between computing devices. There exists a need to provide an improved methodology for managing data transfer between computing devices in this environment.